Title 8 section 1401 subsection G is commonly referred to as The Immigration and Nationality Act. Ted Cruz would have to be an immigrant to the U.S. before title could apply to him. Congress does not have Constitutional authority to pass immigration and nationality legislation that applies to citizens at birth.
Congress has a Constitutional mandate to legislate rules and regulations with respect to aliens and immigrants who wish to become U.S. citizens. Consequently, Cruz had to be an immigrant before Title 8 could be applied to him.
Mr Cruz does NOT need to immigrate for the law to apply to him. Please read the whole of section 1401 and in specific subsection A which states that any person born on US soil is automatically a US citizen at birth. Theses are part of the rules of naturalization specifically as an enumerated power delegated to Congress in Article 1 section 8 of the US Constitution.